The role of certainty (and uncertainty) in attitudes and persuasion

•Psychological certainty plays a key role in attitudes and persuasion.•Attitude certainty has important consequences for thought and action.•People assess their own certainty using informational and experiential inputs.•Inducing uncertainty during message processing can enhance persuasion.

Psychological certainty plays a key role in shaping people's thoughts, judgments, attitudes, and behaviors. This article provides an overview of recent work on attitude certainty, which has been the subject of considerable attention in the social and consumer psychology literatures. In particular, this article describes the consequences of feeling certain or uncertain of an attitude, outlines the metacognitive appraisals that shape people's feelings of certainty or uncertainty, and highlights recent developments suggesting that strategically inducing uncertainty during message processing can enhance message impact. In essence, whereas uncertainty can stimulate processing and create a desire for information, certainty helps give an attitude durability and impact.